He told the BP board that the company's existing Russian partners, Alfa-Access-Renova (AAR), could be squared at a commercial price.

But he misjudged AAR's tactics and cojones. At best BP will have to pay AAR a much higher "commercial" price to proceed with the Rosneft deal than previously anticipated.

AAR's price could be too high, at which point Dudley will walk away leaving the Russians with nothing. That's a risk for them. But it would leave BP with nothing too, which is a much bigger risk for Dudley commercially and reputationally.

Separately, he's embarked on a bid to drive forward with just the share swap with Rosneft, without any strategic Arctic tie-up. That's already fallen foul of an arbitration court. There's obviously a risk it could fail a second time.

But there's another risk: that BP's shareholders could reject the share swap too. Already Standard Life, a top 10 BP shareholder, has rejected the idea.